I initially learned by the rolling and staying down approach too. But try the following:

Have someone stand there with say their right arm extended 90 degrees from your direction (they can face their arm and not you).

You walk to their arm (so that their body in on your right hand side) grab their wrist with your left hand and continue to walk forward.

Let your head drop as if to roll, and reach backwards with your right arm as far away from your back as possible with that right hand nice and relaxed.

When you go over for the fall, your right hand should be so far out there that it certainly hits the floor first. Then the side of your right leg and then your left foot. It should have the rhythm of 3 quick beats. Bum, bum, bum... Then let go of your helpers hand.

It is a little difficult to get your legs adjusted correctly - so I recommend doing this on a nice big mat at first. Also, there might be a lot of muscle memory to battle with to get that backwards arm to stay as far away from the body as possible - but you need that to absorb the blow most efficiently.

I'm not exactly sure how to get video onto the web, but if you send me instructions, I think I can demonstrate it pretty well.

Good luck - Rob

PS (I like the advice about using stomach muscles to control the relaxed legs - great way to say it!)